Rear window shades for motor vehicles are known in the prior art. Today, a rotatably seated winding shaft installed under the rear window ledge is usually a part of these shades. An edge of the shade web is fastened to the winding shaft and can be pulled out through a slit in the rear window ledge. Since the shade web is not rigid in itself, it is necessary for the shade web to be guided. To this end, guide rails, in which a pull rod arrangement is guided, extend at the sides of the side to be shaded. The pull rod arrangement is fastened to the front edge of the shade web, i.e. to that edge which travels the greatest distance when the window shade is extended and retracted.
The guide rails have an approximately C-shaped cross section, so that an undercut channel is created, which opens to the outside via a slit. The slits of the two guide rails face each other. The pull rod arrangement can include guide bodies that can be guided in the guide rails in such a way that the guide bodies cannot be pulled out at right angles to the longitudinal axis of the guide rail.
Although as a rule the guide bodies are pre-tensed by springs, and a spring motor force also acts on the pull rod arrangement which attempts to wind the shade web up on the winding shaft, such arrangements are not completely free of rattles. Force components, which are effective perpendicularly with respect to the plane defined by the extended window shade, are primarily only absorbed by the frictional connection which is used between the guide bodies and the actuating devices for transporting the pull rod arrangement along the guide rails. The forces can easily become larger, and the guide bodies can rattle in the transverse direction. The question as to whether this noise will develop depends on the position of the window shades, the installed position, the jarring being generated because of road conditions, and other factors.
Freedom from rattling cannot be completely assured by means of the previous solutions.